import com.sun.scenario.effect.impl.sw.sse.SSEBlend_SRC_OUTPeer;

import java.util.Scanner;

/**
 * 求解立方根
 * 计算一个浮点数的立方根，不使用库函数。
 */
public class HJ107 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        while (scanner.hasNext()){
            double num = Double.parseDouble(scanner.nextLine());
            double high = 20;
            double low = -20;
            double mid = 0;

            while ((high-low)>0.01 && Math.abs(mid*mid*mid-num)>0.01){
                mid = (high+low)/2;
                if((mid*mid*mid - num) > 0.01){
                    high = mid;
                }else {
                    low = mid;
                }
            }
            System.out.println(String.format("%.1f",mid));
        }
    }
}
